The last section of this chapter deals with another aspect of storage in Linux that some may find confusing. This is Universally Unique Identifiers (UUIDs). You've no doubt seen Linux names storage devices using virtual device files such as /dev/sda, /dev/sdb, and so on. In the preceding sections, you had seen this everywhere, even in the /etc/fstab file when listing the partitions that are mounted each time you start your system, created during installation. However, there was a bit of a problem with this type of system that UUID tried to solve.

In today's day and age, we remove and insert media constantly. A typical desk drawer may contain a plethora of flash drivers, and in the typical desktop PC, we may have multiple hard disks and may add additional storage devices later. Each time we add media to the computer, it is assigned a virtual device file by the kernel. Typically, the first partition on the first hard drive used by Linux...